I have this growing in one of my flower beds. Is this called Nutsedge and if it is, is it a good or bad plant?

It does look like it and if let go will take over the whole bed and spread everywhere. It's difficult to get rid of once established.

While that's a sedge, I can't really say for sure which one.

I have closeups of the seedheads and roots posted here:
(Edit) purple nutsedge.
http://stonethegardener.tumblr...

Have a look, see if you think its the same...

There is a yellow and a purple nutsedge, one is supposed to be edible.

Sometimes growing sedges is desirable... But... Nutsedge generally never.

Nutsedge is horribly aggressive. There is an Ortho spray for it but here it's not available locally. I'd buy it in a second.

It looks a lot like the sedge that grows in some of my pastures - nothing seems to eat it.

It's the "nicest grass" in our mowed area, being upright, NOT climbing or tunneling over or under barriers, soft, & bright green (among bahiagrass & several hideous vine-grasses like Bermuda, St. Augustine, torpedo/wiregrass, all of which make a poor excuse for a lawn, visually and functionally,) but not a plant that is sold or cultivated as "lawn."

10 minutes of pulling should get rid of what you can see above ground in that tiny spot, but even if you think you pulled all of the roots, you probably can't, some will break & remain in the soil. Pull when you see, often enough that it can't make new seeds & you should get control very soon.

Nutsedge does have a nut as shown in this photo. If you don't get the nut your work is in vain - it will continue to spread.

Yes, it can be difficult to determine when pulling if the root structure has been completely removed, even if one is tedious enough when doing to knock off the dirt & inspect the roots of each pulled clump. I don't inspect when pulling but apparently the roots do usually come up cleanly when I pull. I'm not pulling the same ones over & over, not a plant I worry about taking over cultivated beds at all, even though they are surrounded by this plant and all are recently reclaimed, formerly mowed areas.

Yellow Nutsedge (Cyperus esculentus)

OK, finally checked the database.
It appears that you have the less aggressive yellow nutsedge.

This one is edible.
If you must have nutsedge.... Pray for this one.

The purple one is far worse.